O2 induced Cu surface segregation in Au-Cu alloys studied by angle resolved XPS and DFT modelling.
Phys Chem Chem Phys
; 14(20): 7448-55, 2012 May 28.
Article
de En
| MEDLINE
| ID: mdl-22514022
ABSTRACT
Surface segregation effects on polycrystalline Au-Cu alloys (Au(0.80)Cu(0.20), Au(0.85)Cu(0.15) and Au(0.90)Cu(0.10)) were studied at room temperature by angle resolved XPS (ARXPS) and density functional theory (DFT) before and after exposure to O(2). Au surface enrichment was found as predicted from calculations showing that this process is energetically favourable, with a segregation energy for Au in a Cu matrix of -0.37 eV atom(-1). Surface enrichment with Cu was observed after exposure to O(2) due to its dissociative adsorption, in agreement with DFT calculations that predicted an energy gain of -1.80 eV atom(-1) for the transfer of Cu atoms to a surface containing adsorbed oxygen atoms, thus leading to an inversion in surface population.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Type d'étude:
Prognostic_studies
Langue:
En
Journal:
Phys Chem Chem Phys
Sujet du journal:
BIOFISICA
/
QUIMICA
Année:
2012
Type de document:
Article
Pays d'affiliation:
Argentine